In general, a washing machine is a device for cleaning laundry by washing, rinsing, and spin-drying clothes using a detergent and water supplied into a tub. The washing machine includes a pressure sensor capable of properly controlling water supply based on a water level preset in a controller or manually set by a user.
The pressure sensor has a structure in which a metal coil and a magnetic bar move based on a variation in air pressure due to a variation in the water level of a target device, and operates due to frequency oscillation based on a variation in inductance.
Since steam washing machines are currently commercialized, research is being actively conducted on a pressure sensor capable of precisely detecting a water level. However, a pressure sensor may detect an output frequency variation of several kHz, and may not precisely detect a water level because an output value varies in the form of a non-linear quadratic curve. Furthermore, an excessively high pressure may be applied to the pressure sensor due to excessive steam or the pressure of continuously supplied water and, in a worse case, the pressure sensor may be damaged or broken.